1. Field of the Invention
The present invention relates to a drive apparatus for oscillating at least one shaft, the drive apparatus including a lever which is pivotable around a pivot axis and coupled to a drive member which is reciprocable between two end positions. The invention relates further to an apparatus for intermittently feeding a web-shaped workpiece, the apparatus having a pressing roller, a feeding unit cooperating with the pressing roller, and the drive apparatus
2. Description of the Prior Art
A drive apparatus for oscillating shafts and an application of this drive apparatus for driving two counterrotating oscillating feed rollers of an apparatus for intermittently feeding workpieces are disclosed in the U.S. Pat. Nos. 3,758,011 and 3,784,075.
The disclosed apparatus includes a lever which is pivotable around a pivot axis. The lever is mounted to a drive member which is reciprocable between two end positions and includes a rotatably mounted sliding body, which is guided at a slideway included with a rotating member mounted to the shaft to be driven.
The lever of this known apparatus is subjected, among other things, to a rather high torsional loading. The known apparatus features, furthermore, a considerable width. This leads to rather long structural members that are subjected to bending forces, and as well known, that designs having long structural members subjected to bending forces lead to imprecise operation and imprecise products.